1. Field of the Invention
This invention relates to a liquid container, a method of manufacturing the container, the package of the container, an ink jet head cartridge in which the container and a recording head are made integral with each other, and a liquid discharge recording apparatus, and particularly to a liquid container suitably utilized in the field of ink jet recording or the like.
2. Related Background Art
Generally, an ink tank as a liquid container used in the field of ink jet recording is provided with a construction for adjusting the holding force of ink stored in the ink tank to well effect the supply of the ink to a recording head for discharging the ink. This holding force is for making the pressure of the ink discharging portion of the recording head negative relative to the atmosphere and is therefore called negative pressure.
As one of the easiest methods for generating such negative pressure, mention may be made of a method of providing a porous member such as urethane foam or an ink absorbing member such as felt in the ink tank, and utilizing the capillary force (ink absorbing force) of the ink absorbing member. For example, Japanese Laid-Open Patent Application No. 6-15839 discloses a construction in which a plurality of fibers differing in density from one another are compressed and packed in the whole of an ink tank in the order of high-density fiber and low-density fiber toward a supply path to a recording head. The high-density fiber has a great number of fibers per unit area and has a strong ink absorbing force, and the low-density fiber has a small number of fibers per unit area and has a weak ink absorbing force. The seams among the fibers are brought into pressure contact with each other so as to prevent the intermission of ink caused by the mixing of air.
On the other hand, the applicant of the basic application has proposed in Japanese Laid-Open Patent Application No. 7-125232, Japanese Laid-Open Patent Application No. 6-40043, etc. an ink tank provided with a liquid containing chamber of which the ink containing amount per unit area is increased in spite of an ink absorbing member being utilized and which can realize stable ink supply.
FIG. 1A of the accompanying drawings is a schematic cross-sectional view showing the construction of an ink tank utilizing the above-described construction. The interior of an ink cartridge 10 is partitioned into two spaces by a partition wall (38) having a communicating hole (communicating portion) 40. One of the two spaces provides a liquid containing chamber 36 hermetically sealed except the communicating hole 40 of the partition wall 38 and directly holding ink 25 therein, and the other space provides a negative pressure generating member containing chamber 34 containing a negative pressure generating member 32 therein. A wall surface forming this negative pressure generating member containing chamber 34 is formed with an atmosphere communicating portion (atmosphere communicating port) 12 for effecting the introduction of the atmosphere into the container resulting from the consumption of ink, and a supply port 14 for supplying the ink to a recording head portion, not shown. In FIGS. 1A and 1B, the area in which the negative pressure generating member holds the ink is indicated by hatching. The ink contained in the space is indicated by net lines.
In the above-described structure, when the ink in the negative pressure generating member 32 is consumed by the recording head, not shown, air is introduced from the atmosphere communicating port 12 into the negative pressure generating member containing chamber 34, and enters the liquid containing chamber 36 through the communicating hole 40 of the partition wall 38. Instead of this, the negative pressure generating member 32 in the negative pressure generating member containing chamber 34 is filled with the ink from the liquid containing chamber 36 through the communicating hole of the partition wall (this will hereinafter be referred to as the gas-liquid exchanging operation). Accordingly, even if the ink is consumed by the recording head, the negative pressure generating member 32 is filled with the ink in conformity with the consumed amount, and the negative pressure generating member 32 holds a predetermined amount of ink therein and keeps the negative pressure relative to the recording head substantially constant and therefore, the ink supply to the recording head becomes stable. Such an ink tank which is compact and has high use efficiency has been commercialized by the applicant of the basic application and is still used in practice.
In the example shown in FIG. 1A, an atmosphere introducing groove 50 as a structure for expediting the introduction of the atmosphere is provided near the communicating portion between the negative pressure generating member containing chamber and the ink containing chamber, and a space (buffer chamber) 44 free of the negative pressure generating member by ribs 42 is provided near the atmosphere communicating portion.
Also, the applicant of the basic application has proposed in Japanese Laid-Open Patent Application No. 8-20115 an ink tank using as the negative pressure generating member of the ink tank a fiber comprising olefin resin having thermoplasticity. This ink tank is excellent in ink storing stability and is also excellent in recycling property because the ink tank housing and the fibrous material are formed of the same kind of material.
Now, the inventors have zealously studied about a construction using a fibrous material as the negative pressure generating member of the ink tank shown in FIG. 1A with a result that it has been found that the following fact may pose a problem.
That is, when supposing the state before the start of use such as during distribution, the liquid containing chamber has been positioned and left upwardly in the direction of gravity relative to the negative pressure generating member containing chamber, as shown in FIG. 1B of the accompanying drawings, it has been found that by the air being introduced into the liquid containing chamber through the communicating portion, the liquid in the liquid containing chamber may leak to the negative pressure generating member and the ink 25 may overflow to the buffer chamber. If the ink thus overflows to the buffer chamber, the ink may overflow through the atmosphere communicating port to thereby stain a user""s hand or the ink may drop from the liquid supply port to stain the user""s hand or the like when the seal is broken.
The above-noted problem is considered to arise from the following characteristics of the ink absorbing member using fibers as compared with a porous material such as conventional urethane foam:
(1) since porosity is great, the pressure loss of ink movement is small;
(2) the difference between the advancing angle of contact and the retreating angle of contact of the ink with the fiber is small; and
(3) in the case of the ink absorbing member using the fibers, a capillary force is created in the gaps among the fibers and therefore, the difference in the local strength of the capillary force on the scale of the cell (about 80 to 120 xcexcm) of urethane sponge is small as compared with an ink absorbing member formed by cell film being removed after urethane foam is foamed.
This problem peculiar to a construction utilizing a fiber material as the negative pressure generating member has been recognized by the inventors for the first time.
It is a first object of the present invention to provide a liquid container which utilizes a fibrous material as a negative pressure generating member and yet solves the above-noted problem.
It is a second object of the present invention to provide a liquid container having a liquid containing chamber having both of the above-described compactness and high use efficiency and free of inadvertent inflow of liquid from the liquid containing chamber to a negative pressure generating member containing chamber, on the basis of an unconventional, novel idea found out by the inventors"" study for achieving the above first object, i.e., the relation between the hardness and interface of two negative pressure generating members when they are urged against each other.
In addition, it is another object of the present invention to provide a method of manufacturing the above-described liquid container, an ink jet cartridge utilizing the above-described liquid container, etc. which will be described later.
Specific means for achieving the above objects could be understood from the following construction.
The liquid container of the present invention is a liquid container having a negative pressure generating member containing chamber containing therein a negative pressure generating member formed of a fiber material and provided with a liquid supplying portion and an atmosphere communicating portion, a liquid containing chamber provided with a communicating portion communicating with the negative pressure generating member containing chamber and forming a substantially hermetically sealed space and storing therein liquid to be supplied to the negative pressure generating member, and a partition wall for partitioning the negative pressure generating member containing chamber and the liquid containing chamber and forming the communicating portion, characterized by the provision of gas introduction blocking means cooperating with the partition wall and the liquid contained in the negative pressure generating member containing chamber to block the introduction of gas from the communicating portion into the liquid containing chamber except during the supply of the liquid from the liquid supplying portion to the outside.
According to the above-described liquid container, irrespective of the posture of the liquid container, the introduction of gas from the communicating portion into the liquid containing chamber except during the supply of the liquid from the liquid supplying portion to the outside is blocked by the liquid contained in the negative pressure generating member formed of a fiber material and the gas introduction blocking means, whereby the first object is achieved.
On the other hand, during the liquid supplying operation, the liquid is consumed from the negative pressure generating member and therefore, the gas introduction blocking means permits the gas-liquid exchanging operation and can therefore realize a stable liquid supplying operation while keeping the negative pressure in the liquid supplying portion substantially constant.
Also, a liquid container according to another embodiment of the present invention is characterized in that in a negative pressure generating member containing chamber, between a first negative pressure generating member on the communicating portion side with a liquid containing chamber and a second negative pressure generating member on the atmosphere communicating portion side, there is a boundary layer of a capillary force stronger than the capillary force of the second negative pressure generating member, and is structured such that through this layer, the atmosphere communicating portion and the communicating portion with the liquid containing chamber communicate with each other without fail. The liquid container is also characterized in that in the state before the start of use as during distribution, in whatever direction the ink tank may be left as it is, the difference between the capillary force of the second negative pressure generating member and the capillary force of the boundary layer is equal to or greater than the difference between the water head of the ink-atmosphere interface in the second negative pressure generating member and the water head of the ink-atmosphere interface of the boundary layer.
In the above-described construction, the ink-atmosphere interface sometimes flows in the second negative pressure generating member, but it never happens that the ink-atmosphere interface in the boundary layer flows, because the ink in the boundary layer is always held by a capillary force equal to or greater than the difference in water head from the ink in the second negative pressure generating member. Thus, the boundary layer is always filled with the ink and therefore, the atmosphere can be prevented from flowing into the first negative pressure generating member and the liquid containing chamber through the boundary layer. Accordingly, ink exceeding the amount of ink which can be held in the negative pressure generating member containing chamber can be suppressed from flowing in from the liquid containing chamber, thereby achieving the first object. As a further embodiment, the capillary forces of the two negative pressure generating members themselves may be made to differ from each other, instead of the above-described boundary layer strong in capillary force.
Also, a liquid container according to still another embodiment of the present invention is a liquid container having a negative pressure generating member containing chamber containing therein first and second negative pressure generating members urged against each other and provided with a liquid supplying portion and an atmosphere communicating portion, a liquid containing chamber provided with a communicating portion communicating with the negative pressure generating member containing chamber and forming a substantially hermetically sealed space and storing therein liquid to be supplied to the negative pressure generating member, and a partition wall for partitioning the negative pressure generating member containing chamber and the liquid containing chamber and forming the communicating portion, characterized in that the interface of the urged portions of the first and second negative pressure generating members intersects with the partition wall, the first negative pressure generating member communicates with the communicating portion and can communicate with the atmosphere communicating portion only through the interface of the urged portions, the second negative pressure generating member can communicate with the communicating portion only through the interface of the urged portions, one of the first and second negative pressure generating members which is weak in capillary force is harder than the other negative pressure generating member and the negative pressure generating member containing chamber is filled with an amount of liquid which can be held by the entire interface of the urged portions irrespective of the posture of the liquid containing chamber, thereby achieving the second object.
Also, the present invention provides a method of manufacturing the above-described liquid container, a package as a form of the container as during distribution thereof, an ink jet head cartridge in which the container and a recording head are made integral with each other, and a recording apparatus.
The method of manufacturing the liquid container of the present invention is a method of manufacturing a liquid container having a negative pressure generating member containing chamber containing therein a first negative pressure generating member and a second negative pressure generating member urged against each other, the second negative pressure generating member being harder than the first negative pressure generating member, the negative pressure generating member containing chamber being provided with a liquid supplying portion and an atmosphere communicating portion, a liquid containing chamber provided with a communicating portion communicating with the negative pressure generating member containing chamber and forming a substantially hermetically sealed space and storing therein liquid to be supplied to the negative pressure generating members, and a partition wall for partitioning the negative pressure generating member containing chamber and the liquid containing chamber and forming the communicating portion, wherein the interface of the urged portions of the first and second negative pressure generating members intersects with the partition wall, the first negative pressure generating member communicates with the communicating portion and can communicate with the atmosphere communicating portion only through the interface of the urged portions, and the second negative pressure generating member can communicate with the communicating portion only through the interface of the urged portions, characterized by the provision of the preparing step of preparing a main body in which a recess for the negative pressure generating member containing chamber provided with the liquid supplying portion and a recess for the liquid containing chamber are formed integrally with the partition wall provided with the communicating portion, the first inserting step of inserting the first negative pressure generating member into the recess for the negative pressure generating member containing chamber of the main body, the first compressing step of making the first negative pressure generating member bear against the bottom surface of the recess after the first inserting step, and compressing the first negative pressure generating member in the insertion direction while sliding it relative to the inner side of the recess for the negative pressure generating member containing chamber, the second inserting step of inserting the second negative pressure generating member into the recess for the negative pressure generating member containing chamber of the main body after the first inserting step, the second compressing step of urging the second negative pressure generating member against the first negative pressure generating member and compressing it in the inserting direction while sliding it relative to the inner side of the recess for the negative pressure generating member containing chamber, after the first compressing step, and the enclosing step of fixing to the main body a lid member provided with an opening for the atmosphere communicating portion and covering both of the two recesses, thereby forming the negative pressure generating member containing chamber and the liquid containing chamber.
According to the above-described manufacturing method, the first negative pressure generating member which is not hard as compared with the second negative pressure generating member is compressed in advance in the container, thereby making the first negative pressure generating member easy to deform more preferentially when the two capillary force generating members are urged against each other, whereby the intimate contacting property of the surfaces of the two negative pressure generating members which bear against each other and the manufacturing irregularity of the positions of those surfaces relative to the main body of the container can be suppressed. As the result, the above-described container can be manufactured inexpensively and easily.
Also, a method of manufacturing a liquid container according to another embodiment of the present invention is characterized by the step of preparing a liquid container having a negative pressure generating member containing chamber containing therein first and second negative pressure generating members urged against each other and provided with a liquid supplying portion and an atmosphere communicating portion, a liquid containing chamber provided with a communicating portion communicating with the negative pressure generating member containing chamber and forming a substantially hermetically sealed space and storing therein liquid to be supplied to the negative pressure generating members, and a partition wall for partitioning the negative pressure generating member containing chamber and the liquid containing chamber and forming the communicating portion, wherein the interface of the urged portions of the first and second negative pressure generating members intersects with the partition wall, the first negative pressure generating member communicates with the communicating portion and can communicate with the atmosphere communicating portion only through the interface of the urged portions, the second negative pressure generating member can communicate with the communicating portion only through the interface of the urged portions, and the capillary force of the interface of the urged portions is higher than the capillary forces of the first and second negative pressure generating members, the first liquid filling step of filling the liquid containing chamber with liquid, and the second liquid filling step of filling the negative pressure generating member containing chamber with an amount of liquid which can be held by the entire interface of the urged portions irrespective of the posture of the liquid container.
The package of the present invention contains the above-described liquid container therein, and is characterized by the provision of seal means for closing the atmosphere communicating portion and liquid supplying portion of the container, and means for opening the seal means.
Also, the ink jet head cartridge of the present invention is characterized by the provision of the above-described liquid container, and a liquid discharging head portion capable of discharging liquid contained in the container.
The liquid discharging recording apparatus of the present invention is characterized by the provision of the above-described liquid container, a liquid discharging head portion capable of discharging liquid contained in the container, and a mounting portion for the liquid container.
Regarding the insertion of the above-described negative pressure generating members, the form thereof is not restricted to the container provided with the liquid containing chamber.
So, on the basis of the above-described novel idea, a method of manufacturing a liquid container according to still another embodiment of the present invention is a method of manufacturing a liquid container containing thereon a first negative pressure generating member and a second negative pressure generating member urged against each other, the second negative pressure generating member being-harder than the first negative pressure generating member, characterized by the provision of the preparing step of preparing a main body provided with a recess provided with a bottom surface bearing against the first negative pressure generating member, the first inserting step of inserting the first negative pressure generating member into a recess for the negative pressure generating member containing chamber of the main body, the first compressing step of making the first negative pressure generating member bear against the bottom surface of the recess after the first inserting step, and compressing the first negative pressure generating member in the inserting direction while sliding it relative to the inner side of the recess for the negative pressure generating member containing chamber, the second inserting step of inserting the second negative pressure generating member into the recess for the negative pressure generating member containing chamber of the main body after the first inserting step, the second compressing step of urging the second negative pressure generating member against the first negative pressure generating member after the first compressing step, and compressing the second negative pressure generating member in the inserting direction while sliding it relative to the inner side of the recess for the negative pressure generating member containing chamber, and the enclosing step of fixing a lid member for covering the recess to the main body.
According to the above-described manufacturing method, when a plurality of capillary force generating members are inserted into the container, the control of the intimate contact state can be effected easily, and a container provided with a plurality of capillary force generating members can be manufactured easily with little manufacturing irregularity.
In addition, the present invention also provides a container manufactured by the above-described manufacturing method. A liquid container according to yet still another embodiment of the present invention is a liquid container provided with first and second negative pressure generating members urged against each other, a container body provided with a recess containing the first and second negative pressure generating members, and a lid member covering the opening portion of the container body with the first and second negative pressure generating members contained in the container body, characterized in that the second negative pressure generating member is hard as compared with the first negative pressure generating member, the first negative pressure generating member bears against the bottom surface of the recess of the container body, and that surface of the first negative pressure generating member which is opposed to the bottom surface bears against the second negative pressure generating member.
According to the above-described liquid container, a container provided with a plurality of capillary force generating members can be manufactured easily with little manufacturing irregularity by the above-described manufacturing method.
The xe2x80x9chardnessxe2x80x9d of the negative pressure generating members in the present invention is the xe2x80x9chardnessxe2x80x9d of the negative pressure generating members when contained in the liquid container, and is prescribed by the inclination (unit: kgf/mm) of the repulsion to the amount of deformation of the negative pressure generating members.
As regards the magnitude of the xe2x80x9chardnessxe2x80x9d of the two negative pressure generating members, that negative pressure generating member in which the inclination of the repulsion to the amount of deformation is greater is called the xe2x80x9chard negative pressure generating memberxe2x80x9d.